Abstract: Low-dimensional Bi₂Fe₄O₉ nanosheets and microrods have been selectively prepared by a solvothermal method, from which the growth of the Bi₂Fe₄O₉ crystals can be controlled by the variation of reaction conditions. Structure determination showed that the nanosheets are mainly exposed by 001 facets while the microrods are exposed by 110 facets. Ab- sorption spectra revealed that there are two bandgaps observed for both nanosheets (at 1.9 and 1.55 eV) and microrods (1.7 and 1.45 eV), and they both would be available for the sunlight photocatalysis e ciently due to the intensive absorption ability in a wide region. Photocatalytic investigation demonstrated that the overall photocatalytic performance of the microrods is prior to that of the nanosheets due to the variation of bandgaps and exposed facets. The present report provides a useful alternative strategy for the controlling growth of nanostructures and/or microcrystals besides the present demonstration of the Bi₂Fe₄O₉ crystals with diflerent bandgaps and facets that would be able to tune the corresponding photocatalytic ability selectively.